Metastatic Lung Adenocarcinoma to the Appendix: A Case Report

There are few reported cases in the literature of metastasis to the appendix. A 44-year-old patient presented with abdominal pain and changes in the bowel pattern. Thoracic and abdominal computed tomography scans evidenced pulmonary and liver nodules. The pulmonary nodule was biopsied and the hematoxylin-and-eosin (HE) stained slides showed an adenocarcinoma. The immunohistochemistry profile demonstrated positivity for CK7 and TTF-1. The patient underwent an appendectomy. HE stained slides also demonstrated adenocarcinoma infiltrating the entire appendix wall along with the epithelial surface with immunohistochemistry study of the appendix neoplasm showing exactly the same results as seen in the first panel.